In the prior art, a virtual extensible local area network (VxLAN) technology is used to extend network virtualization so as to obtain a sufficient quantity of virtual networks for users.
Virtual machines (VM) of multiple virtual networks may run in each data center. When communicating with a VM of another data center, a VM of a data center may send a broadcast Address Resolution Protocol (ARP) request to a first-hop router to acquire a MAC address of a destination gateway in a broadcast manner, and the ARP request is then broadcast to each VM. After the MAC address of the destination gateway is acquired, a packet is sent to a router of each data center by using the MAC address of the destination gateway, and then arrives at a destination VM, thereby implementing communication between the VMs. However, in this manner of ARP broadcasting to each VM, a large amount of transmission bandwidth is occupied; in addition, a packet can arrive at a destination VM only by passing through the router of each data center, which results in serious roundabout routing among data centers.